This patch fixes possible regression introduced by
patch reworking endpoint claiming mechanism. It restores
setring ep->driver_data to NULL in usb_ep_autoconfig_reset(),
which was removed by patch commit 
cc476b42a39d.
Fixes: cc476b42a39d ("usb: gadget: encapsulate endpoint
	claiming mechanism")
Reported-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
 
        list_for_each_entry (ep, &gadget->ep_list, ep_list) {
                ep->claimed = false;
+               ep->driver_data = NULL;
        }
        gadget->in_epnum = 0;
        gadget->out_epnum = 0;